Magnetic recording medium and process for producing same

Abstract

A magnetic recording medium having a magnetic layer which is formed by dispersing a magnetic powder and further an abrasive when necessary into a binder containing a sugar alcohol. The magnetic recording medium has excellent glossiness, squareness ratio and other surface properties due to the improvement of dispersibility of the magnetic powder and/or an abrasive when necessary.

We claim: 
     
       1. A magnetic recording medium having a magnetic layer which includes a magnetic powder dispersed in a binder, comprising a sugar alcohol adsorbed onto the magnetic powder. 
     
     
       2. A magnetic recording medium according to claim 1, which further comprises an abrasive therein. 
     
     
       3. A magnetic recording medium according to claim 1 or 2 wherein the sugar alcohol is contained in an amount of about 0.5 to about 10% by weight on the basis of the magnetic powder and abrasive weight. 
     
     
       4. A magnetic recording medium according to claim 1 or 2 wherein the sugar alcohol is contained in an amount of about 0.7 to about 5% by weight on the basis of the magnetic powder and abrasive weight. 
     
     
       5. A magnetic recording medium according to claim 1 or 2 wherein the sugar alcohol is selected from the group consisting of sorbitol, mannitol or dulcitol or a mixture thereof. 
     
     
       6. A process for producing a magnetic recording medium having a magnetic layer formed of a magnetic powder and an abrasive where necessary, dispersed in a binder, comprising thoroughly mixing a sugar alcohol with the magnetic powder and the abrasive where necessary and then mixing the resulting mixture with the binder. 
     
     
       7. A process according to claim 6 wherein the sugar alcohol is in the form of a solution in a solvent. 
     
     
       8. A process according to claim 7 wherein the solvent is water or ethanol. 
     
     
       9. A process according to claim 6 or 7 wherein the sugar alcohol is selected from the group consisting of sorbitol, mannitol or dulcitol or a mixture thereof. 
     
     
       10. A process according to claim 7 or 8 wherein a concentration of sugar alcohol in the solvent ranges from about 2 to about 30% by weight. 
     
     
       11. A process according to claim 7 or 8 wherein a concentration of sugar alcohol in the solvent ranges from about 5 to about 20% by weight.